Closure cap for an infusion flask

ABSTRACT

A closure cap which is applied to the closed neck of an infusion flask to provide a sterile seal therefor comprises a tear-off portion which when removed exposes a sealing disc which can be perforated by the canule of a syringe. The sealing disc is cast or moulded within the cap in engagement with the end wall of the cap and the tear-off portion therein, the said portion having at least one projection on its inner face which locally reduces the thickness of the sealing disc by providing an indentation in the disc which identifies a prepared point of perforation. The closure cap can be fixedly connected to the neck of the flask, and locating means may be provided on the cap and the flask to determine a preset rotational position of alignment of the cap and flask.

United States Patent Stadler June 10, 1975 CLOSURE CAP FOR AN INFUSIONFLASK Primary Examiner-George T. Hall [76] Inventor: Reinhard StadlerKarlsruhe Attorney, Agent, or firm-Wenderoth, Lind & Ponack Germany T TA [22] Filed: May 14, 1974 [57] C A closure cap which IS applied to theclosed neck of Appl- N05 469,883 an infusion flask to provide a sterileseal therefor comprises a tear-off portion which when removed exposes[30] Foreign Application Prio ig Dam a sealing disc which can beperforated by the canule Ma 30 I973 German 2327553 of a syringe. Thesealing disc ls cast or moulded within y y the cap in engagement withthe end wall of the cap [52} U 5 Cl 215/24} 215/25], 215/341 and thetear-off portion therein, the said portion havl5 1] Int Cl 6 6 41/50 ingat least one projection on its inner face which lo- [58] Fie'ld 'i'215/247 1 25] 256 cally reduces the thickness of the sealing disc byproviding an indentation in the disc which identifies a prepared pointof perforation. The closure cap can be fixedly connected to the neck ofthe flask, and locat- [561 References Cited ing means may be provided onthe cap and the flask to UNITED STATES PATENTS determine a presetrotational position of alignment of 2,387,955 10/1945 Tilson 215/249 thecap and fl k 3,047,178 7/1962 Poitras et al. 2l5/249 14 Claims, 2Drawing Figures PATENTEB JUN 10 I975 Fig.1

Fig-Z CLOSURE CAP FOR AN INFUSION FLASK FIELD OF THE INVENTION Thisinvention relates generally to infusion flasks, and more particularly toclosure caps for infusion flasks. It is to be understood that the terminfusion flasks" as used throughout this specification and the appendedclaims is intended to embrace any medical or pharmaceutical containercontaining an injectant that can be drawn out through the canule of asyringe, and that the closure caps of the invention are applicable tothe closure of all such containers.

DESCRIPTION OF THE PRIOR ART It is already known in the art to close aninfusion flask by means ofa closure cap which is applied to the closedneck of the flask and provides a sterile seal. The cap contains asealing disc and has an integral cap portion which can be torn open ortorn off to uncover the sealing disc when the infusion flask is to beused. After the removal of this tear-off portion of the cap theunderlying surface of the sealing disc is exposed. The sealing disc iscapable of being perforated after it has been uncovered and exposed inthis fashion. For the purpose of facilitating perforation of the sealingdisc as by the canule of a syringe, the disc is provided with a preparedpoint in the form of an indentation where perforation is to take place.

In infusion flasks which have been moulded from plastics material andclosed on a machine a parting seam is formed across the closure surface,along the neck and along the flask. The material is naturally thickerwhere the parting seam is located. Such a seam is not visible after theremoval of the tear-off cap portion, and the presence of this seam maybe a major nuisance when the disc is being perforated and it may beresponsible for bending the capsule of a syringe. It has therefore beenfurther proposed to locate the prepared point of perforation so that theparting seam cannot be an obstruction to perforation, by providing theclosure cap, the sealing disc and the neck of the flask with loeatingmeans which when aligned in a prescribed manner, ensure that the pointof perforation is suitably positioned. However, the provision of suchlocating means complicates production and raises the cost.

OBJECT OF THE INVENTION It is therefore a primary object of the presentinvention to provide a closure cap for infusion flasks, which issuitably contrived to simplify production on a mass production basis andto improve the serviceability of the closure above that of conventionalforms of construction.

SUMMARY OF THE INVENTION A closure cap for application to the closedneck of an infusion flask to provide a sterile seal therefor, the capcomprising a skirt adapted to embrace the neck of the flask and an endclosure wall, a sealing disc cast or moulded in engagement with theinner face of the end closure wall, a tear-off cover portion integrallyformed in the end closure wall whereby the sealing disc is exposedthrough the end closure wall when said cover portion is removed, and atleast one projection on the inner face of said cover portion whichlocally reduces the thickness of the sealing disc for perforation.

The above form of construction of the closure cap provides a number ofimportant advantages. The pro duction of the closure cap can beconsiderably simplified by injection moulding or casting the sealingdisc into the cap. The indentation in the sealing disc which identifiesthe prepared point of perforation and is produced by the at least oneprojection in the tear-off cover portion which locally reduces thethickness of the sealing disc, is in a predetermined position inrelation to the closure cap. The material forming the sealing disc canbe sterilised in production, so that a sterile surface for perforationis exposed when the cover portion is removed. The indentationidentifying the point of perforation is automatically produced when thesealing disc is moulded or cast.

Conveniently the closure cap may be made in a plastics material, or in ametal such as aluminium. However, generally speaking the use of aplastics material appears to offer advantages in convenience andcheapness of production costs.

Suitable materials for forming the sealing disc include a large numberof rubber-elastic compositions which can be formed by a moulding orcasting process. A particularly suitable material is an unvulcanisedcalendered natural rubber, a disc of which can be moulded byvulcanisation in situ in the cap.

The use of injection moulding and/or vulcanisation techniques in themoulding process offer advantages in that moulding temperature isusually sufficiently high to sterilise the surfaces of the resultantsealing disc, so that no separate sterilisation procedures are required.For example, a temperature of C would appear to be possible and wouldgive rise to a sealing disc having sterile surfaces after the mouldingprocess.

Particularly suitable plastics materials for the closure cap includepolyethylene, polyvinyl chloride and polypropylene, which can also besatisfactorily heat sealed. It is desirable that the materials chosenfor the closure cap and the sealing disc should be such that thetear-off cover portion will detach from the surface of the sealing discwithout sticking thereto.

If the infusion flask is formed with a peripheral collar on the neck ofthe flask, it may be useful to attach the closure cap to the collar,Suitable the closure cap may be bonded to the collar as by theemployment of suitable adhesives or by welding, or the cap may beattached to the collar by use of an additional metal or plastics coatedflanging ring.

Moreover, it may be advantageous for the closure cap to be a snap-fitonto the neck of the collar. This may be achieved, for example, byforming the skirt of the closure cap in a manner such that it is adaptedto snap onto the neck of the flask. The neck of the flask may be formedwith an undercut shoulder and an internal peripheral rib on the skirt ofthe cap may be engaged beneath the shoulder. This arrangement could, ofcourse, be reversed by providing a rib on the neck of the flask and ashoulder on the skirt of the cap. The provision of a snap-fit connectionof such a kind provides an additional means of safely holding theclosure cap in positionv A convenient method of producing a closure capof the abovedescribed kind comprises filling a mouldable sealing discmaterial into the cap and moulding the sealing disc offset material insitu in the cap at a temperature high enough to sterilise the surfacesof the sealing disc.

Since the formation of the indentation establishing the point ofperforation in the sealing disc occurs at the time the sealing disc isproduced by moulding the disc material in the cap, and the position ofthis indentation in relation to the cap is thus assured, such a closurecap can be very conveniently located in relation to the parting seam ofa plastics flask by providing means on the flask and on the cap forlocating the flask and cap in a predetermined relative rotationalposition, thus permitting the closure cap to be applied to the flask ina production machine and the prepared point of perforation to beautomatically located away from the parting seam and/or any otherundesirable surface regions of the infusion flask.

Such locating means may with advantage comprise flat surfaces on atleast one side of the cap and the flask respectively adapted whenaligned or registered to determine the rotational position of the caprelative to the flask.

The above and further features and advantages of the invention will nowbe more fully described with reference to the accompanying drawings,which illustrate a preferred embodiment of the invention somewhatschematically.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a section of a closure capaccording to the invention applied to the neck of an infusion flask, and

FIG. 2 is a top plan view of the cap in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 of theaccompanying drawings, there is shown an infusion flask made of asynthetic plastics material. The infusion flask has a neck 2 on which isformed a peripheral collar 12. The parting seam of the flask, whereatthe material is thickest, is indicated by the line 13.

The neck 2 of the infusion flask is embraced by the skirt 3a of aclosure cap 3 which also comprises an integral end closure wall 4.having a tear-off cover portion 4a integrally formed therein. Tearoffcover portion 4a is defined by an annular groove 16 extending intoclosure wall 4 from the inner face 4b thereof. With cover portion 4a inplace, the cap 3 is sealed. A ring-shaped finger grip 5 is provided oncap 3. By gripping grip S and pulling the cover portion 4a is torn offaround groove 16 which constitutes a predetermined line of weakening inthe end closure wall 4. In order to facilitate tearing off the coverportion 4a the end wall 4 may further be provided with a point ofpreferential initial fracture, such as a triangular nib adjoining groove16 at a selected point.

The mouth 7 of the infusion flask 1 is sealed by a sealing disc 6 whichhas been formed by moulding or casting a compounded rubber material intothe cap 3 in engagement with the inner face 4b of the end closure wall4. At least one protuberance or projection 8 on the un derside of thecover portion 4a projects into the sealing disc 6. Projection 8 issuitably in the form ofa boss integral with the cover portion 4a. Theprojection 8 locally reduces the thickness of the sealing disc andprovides a prepared location for effecting perforation of the sealingdisc 6 by the canule of a syringe (not shown) once the cover portion 4ahas been torn off.

Cap 3 is an injection moulded plastics material which does not stick tothe surface of the material constituting the sealing disc 6.

The inner surface of the skirt 3a of the closure cap 3 is formed withprojecting peripheral rib or flange 9 which by snap-action engagesbeneath an undercut shoulder 10 encircling the neck 2 of the flask. Therim of the closure cap 3 is further formed with a flange 11 which can bebonded to the peripheral collar 12 on the neck of the flask by hotsealing, with an adhesive or by like means or with the aid of a flangingring (not shown) to firmly attach the closure cap 3 to the flask l.

Locating means are preferably provided on the closure cap 3 and on theneck 2 of the flask for locating these parts in a predeterminedrotational position when the cap is being fitted onto the flask, forexample to ensure that the prepared point of perforation is not near theparting seam 13 of the flask or near some other undesirable part of thesurface of the flask. The locating means suitably comprise flat surfaceson at least one side of the closure cap 3 and the flask 1. In theembodiment shown, the locating means comprise diametrically opposedpairs of flats 14 on the closure cap 3 and flats 15 on the collar 12 ofthe neck 2 of the flask l which permit corresponding parts of thecircumference of the cap 3 and of the neck 2 to be mechanically alignedin a bottle closing machine.

When casting or moulding the material comprising the sealing disc 6 intothe cap 3, the moulding process carried out in situ in the cap ispreferably carried out at a temperature which is high enough tosterilise the surfaces of the sealing disc. Thus, an unvulcanised calendered natural rubber disc may be vulcanised in situ in the cap andsterilised automatically in the course of the vulcanisation. When aninjection moulding process is used to form disc 6, the temperature ofthe material will normally be high enough to ensure sterilisation of thematerial in producing the disc.

A sterile surface of the sealing disc is thus exposed when the coverportion 4a is torn off.

It is to be understood that the embodiment described herein is merelyillustrative of the principles of the invention. Various modificationsthereto may be effected by a person skilled in the art without departingfrom the spirit and scope of the invention.

I claim;

1. A closure cap for application to the closed neck of an infusion flaskto provide a sterile seal therefor, the cap comprising a skirt adaptedto embrace the neck of the flask and an end closure wall, a sealing disccast or moulded in engagement with the inner face of the end closurewall, a tear-off cover portion integrally formed in the end closure wallwhereby the sealing disc is exposed through the end closure wall whensaid cover portion is removed, and at least one projection on the innerface of said cover portion which locally reduces the thickness of thesealing disc for perforation.

2. A closure cap according to claim I, wherein the at least oneprojection comprises a boss integral with said cover portion.

3. A closure cap according to claim 1, wherein the sealing disccomprises an injection moulded elastomer.

4. A closure cap according to claim I, wherein the sealing disccomprises a natural rubber and is moulded by vulcanising the material insitu in the cap.

5. A closure cap according to claim 1 which comprises a syntheticplastics material.

6. A closure cap according to claim 1, wherein said tear-off coverportion is defined by an annular groove which constitutes apredetermined line of weakening in said end closure wall and said wallfurther comprises a point of preferential initial fracture adjoiningsaid groove.

7. An infusion flask comprising the closure cap as claimed in claim 1and a peripheral collar on the neck of the flask to which said closurecap is attached.

8. An infusion flask according to claim 7 wherein the closure cap isbonded to the collar.

9. An infusion flask comprising the closure cap as claimed in claim 1and the skirt of the cap is adapted to snap onto the neck of said flask.

10. An infusion flask according to claim 9, wherein one of said neck andskirt has an undercut shoulder and the other of said neck and said skirthas a peripheral rib engaged beneath said shoulder.

11. An infusion flask comprising the closure cap as claimed in claim 1and means on said flask and said cap for locating said cap and flask inpredetermined relative rotational position.

12. An infusion flask according to claim 11, wherein said locating meanscomprise flat surfaces on at least one side of said cap and said flaskrespectively adapted when aligned to determine the rotational positionof said cap relative to said flask.

13. A method of manufacturing a closure cap as claimed in claim 1 whichcomprises filling a mouldable sealing disc material into the cap andmoulding the sealing disc of said material in situ in the cap at atemperature high enough to sterilise the surfaces of the sealing disc.

14. A method according to claim 13, wherein the moulding processemployed is an injection moulding process.

1. A closure cap for application to the closed neck of an infusion flaskto provide a sterile seal therefor, the cap comprising a skirt adaptedto embrace the neck of the flask and an end closure wall, a sealing disccast or moulded in engagement with the inner face of the end closurewall, a tear-off cover portion integrally formed in the end closure wallwhereby the sealing disc is exposed through the end closure wall whensaid cover portion is removed, and at least one projection on the innerface of said cover portion which locally reduces the thickness of thesealing disc for perforation.
 2. A closure cap according to claim 1,wherein the at least one projection comprises a boss integral with saidcover portion.
 3. A closure cap according to claim 1, wherein thesealing disc comprises an injection moulded elastomer.
 4. A closure capaccording to claim 1, wherein the sealing disc comprises a naturalrubber and is moulded by vulcanising the material in situ in the cap. 5.A closure cap according to claim 1 which comprises a synthetic plasticsmaterial.
 6. A closure cap according to claim 1, wherein said tear-offcover portion is defined by an annular groove which constitutes apredetermined line of weakening in said end closure wall and said wallfurther comprises a point of preferential initial fracture adjoiningsaid groove.
 7. An infusion flask comprising the closure cap as claimedin claim 1 and a peripheral collar on the neck of the flask to whichsaid closure cap is attached.
 8. An infusion flask according to claim 7,wherein the closure cap is bonded to the collar.
 9. An infusion flaskcomprising the closure cap as claimed in claim 1 and the skirt of thecap is adapted to snap onto the neck of said flask.
 10. An infusionflask according to claim 9, wherein one of said neck and skirt has anundercut shoulder and the other of said neck and said skirt has aperipheral rib engaged beneath said shoulder.
 11. An infusion flaskcomprising the closure cap as claimed in claim 1 and means on said flaskand said cap for locating said cap and flask in predetermined relativerotational position.
 12. An infusion flask according to claim 11,wherein said locating means comprise flat surfaces on at least one sideof said cap and said flask respectively adapted when aligned todetermine the rotational position of said cap relative to said flask.13. A method of manufacturing a closure cap as claimed in claim 1 whichcomprises filling a mouldable sealing disc material into the cap andmoulding the sealing disc of said material in situ in the cap at atemperature high enough to sterilise the surfaces of the sealing disc.14. A method according to claim 13, wherein the moulding processemployed is an injection moulding process.